Effect of EDTA on α-HH Crystal Shape Control Based on Experiment and DFT Calculations
DU Jingwei
ZHI Xiao
ZHU Jianping
LIU Songhui
SI Yachao
Abstract：To explore the high value-added utilization of titanium gypsum,ethylene diamine tetraacetic acid(EDTA)was used as crystal modifier to study the feasibility of preparing α-hehi-hydrated gypsum(α-HH)from titanium gypsum and to reveal its effect on the crystal shape control.The results show that the carboxylic acid in EDTA forms a coordination adsorption with Ca2+,which produces differences in adsorption energies at different crystal planes leading to different production rates at each crystal plane through prolonged reaction time.Due to the stronger adsorption at the top than at the end faces,the growth of crystals along the vertical axis is weakened and the growth along the horizontal axis is enhanced.Short columnar α-HH with an aspect ratio of 1.09∶1 is prepared at a dosage of 0.1%EDTA,but with increasing dosage the overgrowth in the horizontal axis is prone to produce a plate-like crystalline shape,which is unfavorable for the preparation of short columnar α-HH.
Keywords：titanium gypsumethylene diamine tetraacetic acid(EDTA)density functional theory(DFT)adsorption energycrystal shape control
Publication Date：2025-03-31
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 217-226 )